1. Field of the Invention
The present invention relates to a throttle control device including a double-system sensor, and more particularly, relates to a throttle control device which controls a throttle in consideration of an abnormal state of the double-system sensor.
2. Description of the Related Art
Japanese Publication for Opposition No. 6-94820 discloses an electronic control device which detects an abnormality of a double-system accelerator position sensor including a main sensor and a sub-sensor. This electronic control device displays an error message on a display device when the difference between signals output from the main sensor and the sub-sensor exceeds a predetermined threshold value, thereby indicating that an abnormality has been detected in the accelerator position sensor.
However, the Publication has not considered the case where the variation degree of the output of the double-system sensor changes when the contact resistance between a resistor and a brush of the double-system sensor increases.
More specifically, the variation degree of the output of the double-system sensor changes depending on the detection position of the double-system sensor when the contact resistance increases. This has been found by the inventors of the present invention. Therefore, in the conventional method in which the double-system sensor is judged abnormal when the difference between the signals output from the double-system sensor exceeds a predetermined value, the precision of the abnormality detection is low.
In view of the foregoing, the objective of the present invention is to provide a throttle control device which can detect an abnormality of a double-system sensor with high precision irrespective of a change in the variation degree of the output of the double-system sensor.